Ski sharpeners in which file blades are held in a variety of ways are known in the art. In one of the known file holders, for example that described in the German Offenlegungsschrift No. 23 46 717, (Mar. 27, 1975, Kollmeder), the file holder has a slot which receives the file blade and is provided with a thumb screw which penetrates the wall of the holder and enters the slot, thereby holding the file blade by pressure. The thumb screw is knurled, permitting manual release, but it is unable to hold the file without chattering and causes damage to the file blade due to the extremely high local pressures exerted by the tip of the screw onto the teeth of the file, causing breakage of the file teeth. The inability of a single screw to hold the file blade securely in place causes it to be incapable of clean sharpening of the edge of an object, in particular the edge of skis. Moreover, the above-described device is intended to be used only within a shop environment so that tools for loosening the screw would normally be available, thereby making the possibility of manual release relatively superfluous.
Another device for filing the guide edges of skis is known from the German Gebrauchsmuster No. 69 19 027, (June 6, 1969, Ammerhofe), which describes a file holder in which a file is clamped between a main guide body and a clamping dog made of wood or the like. The clamping dog is attached to the guide body with screws. The main body of the holder has guide surfaces for receiving the base or the side surfaces of the ski. In this known device, the file may be released only by means of workshop tools.
Another known ski sharpening device is known from the German Gebrauchsmuster No. 76 06 126, (Aug. 5, 1976, C. O. Oberg and Company), which describes a file holder with a recess, the ends of which include support ribs while the file blade is held in place by a central screw. The application of force by the central screw causes an axial bending of the file which produces an effective cutting surface, especially for hard materials. The clamping and release of the file and the holder is possible only by means of shop tools. The point support of the file blade causes breakage of the file teeth.
Finally there is known from U.S. Pat. No. 3,670,601, (Jan. 27, 1976, Howard), a file holder for sharpening skis in which a file blade is held in a holder by being clamped at its ends with the aid of two covers which are urged toward one another by a traversing rod equipped with a thumb screw. This manner of mounting the file blade does not insure secure and rattle-free attachment.
Still further known are devices for filing the edges of skis, etc. in which a holder is provided with a simple slot into which a file blade is inserted. These devices all are unable to secure chatter-free holding of the file blade.